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SECTIONFIVE Conclusions and Recommendations URS was requested by Climax to perform an independent check of the seepage and stability analyses for 3 Dam to satisfy the DRMS third -party review requirements prior to initiating deposition activities. Seepage analyses were completed for 3 Dam to calibrate the existing phreatic surface and predict future phreatic levels during active deposition. Slope stability analyses for 3 Dam included evaluating steady -state and post - earthquake loading conditions for the existing height and the future design height using current seepage analysis results under the operating conditions. Presented below is a summary of conclusions followed by recommendations for further actions. Conclusions and recommendations were developed based on the results of the analyses and on our experience with these and other tailing dams. 5.1 CONCLUSIONS Steady -state seepage and post - earthquake stability analyses were completed for the dam at its existing height for the operating condition. The phreatic surface was based on values calculated using a revised seepage model. Liquefaction analyses completed indicated the material has a low risk for liquefaction under the design earthquake. The stability results for the maximum dam section, presented in Table 4 -3, indicate the dam meets or exceeds the minimum FS design criteria. Steady -state seepage and post - earthquake stability analyses were also completed for the future design height for the design earthquake. The proposed future height is a 13 -foot increase to the raise berm that is stepped back from the existing dam crest. The phreatic surface was based on the current seepage model that showed a slight increase in the phreatic surface due to active deposition. Liquefaction analyses completed indicated the material has a low risk for liquefaction under the design earthquake. The stability results for the maximum dam section, presented in Table 4 -3, indicate the dam meets or exceeds the minimum FS design criteria. Our stability analysis results confirm the dam meets steady -state and post - earthquake stability criteria for both existing height and future design elevations under operating conditions. 5.2 RECOMMENDATIONS The operation of 3 Dam will depend on the proper management of the tailing facility and emplacing tailing with properties envisioned for this dam. With a new mill, it will be important to observe and capture the material properties and changes and evaluate potential impacts tailing operations may have on operation of the facility. Comparing deposited mill tailing with those presently emplaced is important to the overall successful operation of the facility and part of what is known as the "observational approach." The observational approach consists of evaluating the in -place tailing properties with those modeled in the original analysis. It is an iterative process that occurs throughout the life of the dam. With this in mind, we recommend the following actions when deposition resumes: > Perform beach profile sampling to evaluate newly deposited tailing to verify the material properties are consistent with those envisioned in the design. This will include evaluating the whole tailing gradation as it compares to past whole tailing gradations. Profile sampling should be performed near the end of the first spigot season (estimated late summer /early fall 2012). The sampling includes collection of relatively undisturbed UM N IPROJECTS122242095 _CLIMAX STARTUP PROJISUB 881120 WORD PROCI3 DAM SEEPAGES TABILRYTINALWINAL _3 DAM ANALYSES RPT R4 DRMS DOCX 5 -1